Heat transfer apparatus



p 13, 1956 J. R. SHIELDS 3,272,259

HEAT TRANSFER APPARATUS Original Filed June 11, 1962 2 Sheets-Sheet 1 HG. I

OOOOOOOOO 000000000 000000000 ATTORNEY.

INVENTOR. JAMES R. SHIELDS.

Sept. 13, 1966 J. R. SHXELDS 3,272,259

HEAT TRANSFER APPARATUS Original Filed June 11, 1962 2 Sheets-Sheet 2 INVENTOR.

JAMES R. SHIELDS.

ATTORNEY,

PO 9' Ll.

United States Patent 3,272,259 HEAT TRANSFER APPARATUS James R. Shields, Pittsburgh, Pa., assignor to Carrier Corporation, Syracuse, N.Y., a corporation of Delaware Original application June 11, 1962, Ser. No. 201,394.

Divided and this application Oct. 17, 1963, Ser.

3 Claims. (Cl. 165-158) This application is a division of my copendfng application, Serial No. 201,394, filed June 11, 1962, entitled Heat Transfer Apparatus, and relates to heat exchanger construction.

This invention relates broadly to heat transfer apparatus. More particularly, this invention relates to an improved heat transfer unit for exchanging heat between two fluids.

In heat transfer apparatus of the kind under consideration, there is provided a shell assembly forming an enclosure and a tube assembly associated with the shell for the purpose of accommodating a cooling medium, The tube assembly is arranged within the shell so that when fluid is introduced into the shell it passes in heat transfer relation with the tube bundle or assembly accommodating the cooling medium. The fluid introduced into the shell rejects its heat to the cooling medium flowing within the tube bundle.

This invention contemplates an arrangement whereby the fluid introduced into the shell flows downwardly over a tube assembly and then flows upwardly through a path adjacent the tube assembly, but separated therefrom to an outlet in the shell. By changing direction of the flow of fluid introduced into the shell, condensate that may have formed on the surface of the tubes is flung by centrifugal force to the bottom of the heat transfer unit.

Accordingly, it is the chief object of this invention to provide a heat transfer unit of the kind contemplated wherein the unit is arranged so that condensate that may be entrained in the flow of fluid from the unit is separate-d by centrifugal action and drained to waste.

A further object of this invention is the provision of an arrangement for use with heat transfer equipment of the kind described, effective to separate and drain condensate formed in the equipment without introduc ng an undesirable pressure drop in the fluid stream being cooled.

A still further object of the invention is the provision of an arrangement for disposing of condensate formed in heat transfer equipment that effectively prevents the re-introduction of condensate into the cooled gas stream by either entrainment or evaporation.

Another object of the invention is the provision of a unit of the kind under consideration wherein the tube assembly is arranged and constructed so as to be easily inserted through an opening in the shell member into the enclosure formed by the shell. With such an arrangement, it is a relatively easy task to remove the tube assembly for the purpose of repairing leaks between tubes and support sheets or plates.

An additional object of the invention is the provision of an improved method of effecting heat transfer between two fluids wherein the fluid rejecting its heat flows through a path arranged so that condensate from the fluid is separated by centrifugal action as the fluids flows through the heat transfer unit.

Another object of the invention is the provision of an improved method of exchanging heat between two fluids, one of which is a gas subject to condensation under circumstances where the condensate is drained from the gas stream.

Other objects and features of the invention will be apparent upon a consideration of the ensuing specification and drawing in which:

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FIGURE 1 is a perspective view of a heat transfer unit constructed in accordance with the invention;

FIGURE 2 is a view taken in section along lines II-II of FIGURE 1 illustrating the internal arrangement between the tube assembly and the shell assembly; and

FIGURE 3 is a view in section taken along lines III- III of FIGURE 2 illustrating further the arrangement shown in FIGURE 2.

Referring more particularly to the drawings for an illustration of a preferred embodiment of the invention, a shell assembly 10 is employed in conjunction with a tube assembly or tube bundle 12 to form the heat transfer unit.

Shell assembly 10 includes spaced side members 14 and 16 formed of relatively thick material for the purpose of withstanding relatively high pressures such as are encountered in heat transfer units of the kind under consideration when employed as intercoolers between stages of a centrifugal gas or fluid compression plant.

Connecting the lower edges of the side members is a base member 18 formed as illustrated in FIGURE 1 in the form of a semi-circle. It will be noted that the base 18 is formed of a relatively thin material when compared with that employed in the fabrication of side members 14 and 16 In order to complete the enclosure there are provided end members 20, 22 and 24, a top member 26 and front members 28, 30 and 32. The members 28, 30 and 32, are arranged so as to form a frame 33 constituting an opening permitting access to the interior of the shell assembly. An inlet 36 for the purpose of supplying relatively high temperature fluid to the shell assembly is provided in the top member. Likewise disposed in the top members of the assembly is an outlet 38 spaced from the inlet and separated therefrom by a partition 40 depending from the top of the shell in the manner shown in FIGURE 2. Partition 40 serves to define the path of flow for the relatively high temperature fluid introduced into the shell. One of the most important features of the invention resides in the construction employed to separate and remove condensate from a gas stream as it flows through the heat transfer unit. It is well known that baffles may be inserted in a gas stream to remove condenate entrained in the stream. Such an arrangement is objectionable for it introduces a pressure drop in the gas stream, elevating power requirements to offset horsepower loss due to the pressure drop. Additionally, it is effective usually only where gas velocities of a low order such as seven to twelve feet per second are encountered. This means high flow areas and cost if low velocities are employed. If higher velocities are employed separation efliciency is too poor. Another objection to a bafflle-type arrangement is the need for care and maintenance. Unless an expensive maintenance program is followed separation efliciency drops and power consumption rises.

In order to overcome these disadvantages an arrangement for support by existing shell structure is provided. overlying the inner surface of the base member is a flexible cover or blanket member 42 formed of metallic material interwoven in a plurality of layers of strips for the purpose of receiving condensate from the gas stream supplied to the heat transfer unit in a manner to be more particularly described. If desired, certain plastic material or fiber glass materials may be used to form the blanket. The metallic blanket 42 in addition to engaging the sides of the base member is supported by a :perforated shelf 46 connected to the inner surface of the base to form a chord of the are generated by the base in the manner shown in FIGURE 2.

With the member 42 arranged to cover the surface of the base defining the portion of the path of gas flow subject to turning, condensate is deposited thereon by centrifugal action as later described. Without the member 42, condensate would collect in films and a small pool and be re-entrained by the suction of thegas stream en-, tering the upward part of the flow path from the curved portion. The surface of the interwoven metallic member 42 presents an uneven, rough exterior to the droplets deposited therein. The fine filaments capture and hold the drops by surface tension. Since the flow is stagnant below the first few layers of strips re-entrainment is difficult, if not impossible, for the condensate must be entrained through a tortuous passage discouraging such flow. Another advantage in using the structure described is the use of surface tension effects in combination with gravity to effectively drain the condensate.

For the purpose of accommodating the flow of the relatively cool medium such as water, there is provided a tube bundle assembly 12, together with support members located within the shell construction. To this end, it is to be noted that opposed angle members 47 and 48 extend coextensive with the length of the heat transfer unit and are secured to the surface of the partition 40 and the inner surface of side member 14 as shown in FIGURE 2.

The tube bundle assembly comprises tube support sheets 50 and 51, together with a plurality of tubular members 52 extending between the opposed tube sheets, side members 53 and 54, the upper portions of which are provided with flanges adapted to rest on the upper surface of support members 47 and 48. A flexible flap member 57 formed of rubber is provided between the tube assembly and the support members 47 and 48 to prevent bypass of gas introduced into the shell for flow over the tube bundle. In addition, a flexible tubular member 58 is provided for the purpose of preventing loss of high temperature gas in the space between the tube assembly and the partition.

The tube assembly includes a cover 59 forming reversing chamber 60 provided for the purpose of collecting water introduced into the lower group of the tubes from a supply header and routing it through the next higher portion to the supply header for return flow to define a conventional circuit flow through a tube bundle. In addition to a the components of the tube assembly described, there is a water box '62 which is adapted to be connected to the tube sheet 50 adjacent the opening of the shell and is connected together with the tube sheet to the frame provided on the shell assembly.

Considering the operation of the invention, assembly of the tube bundle unit 12 with the shell assembly is accomplished by securing the cover 59 to the rearward tube support sheet 51 proportioned to clear the opening formed by frame 33. The tube assembly is then inserted as a core into the shell 10 with the flanges on 53 and 54 in sliding engagement with supports 47 and 48 until engagement with shelf 61 occurs. Tube support sheet 50 is slightly larger in size than tube sheet 51 so as to engage frame 33 and be fastened thereto. Water box 62 and end cover 63 are then secured to the unit to complete the assembly.

Relatively high temperature fluid such as compressed gas is introduced through the inlet to the interior of the shell assembly. The high temperature gas flows over the tube bundle which has provided therein a supply of cooling medium such as Water arranged to flow upwardly through the tube bundle so as to effect heat transfer between the gas stream and the water. As the temperature of the gas stream is lowered condensate may form on the surface of the tube assembly. The condensate may be 65 entrained in the gas stream flowing through the shell.

However, with the construction described the gas stream flows through a path including a firstdownward portion, a second upward portion between the partition and side member 14, and a curved intermediate portion connecting the first two portions. As the gas stream changes direction in the intermediate portion the condensate entrained therewith is deposited by centrifugal action on the cover member 42 lining the bottom of the base member. The condensate drains from the surface of the member 42 in the manner described. With the construction described, it will be obvious that the gas leaving the heat transfer unit is relatively free of condensate minimizing possibility of cavitation damage if the cooled gas stream is to be compressed further. Support feet '64 serve to connect the heat transfer unit to support structure, not shown, employed to accommodate a gas compression plant of which the heat transfer unit is a component.

While I have described a preferred embodiment of my invention, it will be understood the invention is not limited thereto but may be embodied within the scope of the following claims.

I claim:

1. Heat transfer apparatus comprising a shell assembly defining an enclosure having an end opening and including opposed side members formed of relatively thick material, a base member of semi-circular configuration in cross-section depending from and connecting the lower ends of the opposed side members, means connecting one pair of ends of said side member with the adjacent edge of said base member to form an end closure, a top cover having an inlet and an outlet for said enclosure, a partition depending from the top cover but terminating short of the base to form a gas flow path from the inlet downwardly between the partition and one side to the bottom of the apparatus and upwardly between the partition and other side to the outlet; and a tube assembly comprising spaced tube sheets, a plurality of tubular members connecting said tube sheets, side members coextensive with said tubes connecting the tube assembly to the partition and one of said shell side members, reversing flow means in communication with said tubular members secured to one of said tube sheets, said tube assembly being constructed so that the end supporting said reversing flow means may be inserted into the enclosure and the tube assembly supported therein.

2. Apparatus as set forth in claim 1 wherein one of said tube sheets is arranged to engage the portion of the shell forming the periphery of the end opening through which the tube assembly is inserted.

3. Apparatus as set forth in claim 2 including means for supplying a cooling medium to the apparatus for flow through said tube assembly in heat transfer relation with gas flowing in said gas flow path.

References Cited by the Examiner ROBERT A. OLEARY, Primary Examiner.

CHARLES SUKALO, FREDERICK L. MATTESON,

111., Examiners.

T. W. STREULE, Assistant Examiner. 

1. HEAT TRANSFER APPARATUS COMPRISING A SHELL ASSEMBLY DEFINING AN ENCLOSURE HAVING AN END OPENING AND INCLUDING OPPOSED SIDE MEMBERS FORMED OF RELATIVELY THICK MATERIAL, A BASE MEMBER OF SEMI-CIRCULAR CONFIGURATION IN CROSS-SECTION DEPENDING FROM AND CONNECTING THE LOWER END OF THE OPPOSED SIDE MEMBERS, MEANS CONNECTING ONE PAIR OF ENDS OF SAID SIDE MEMBER WITH THE ADJACENT EDGE OF SAID BASE MEMBER TO FORM AN END CLOSURE, A TOP COVER HAVING AN INLET AND AN OUTLET FOR SAID ENCLOSURE, A PARTITION DEPENDING FROM THE TOP COVER BUT TERMINATING SHORT OF THE BASE TO FORM A GAS FLOW PATH FROM THE INLET DOWNWARDLY BETWEEN THE PARTITION AND ONE SIDE TO THE BOTTOM OF THE APPARATUS AND UPWARDLY BETWEEN THE PARTITION AND OTHER SIDE TO THE OUTLET; AND A TUBE ASSEMBLY COMPRISING SPACED TUBE SHEETS, A PLURALITY OF TUBULAR MEMBERS CONNECTING SAID TUBE SHEETS, SIDE MEMBERS COEXTENSIVE WITH SAID TUBES CONNECTING THE TUBE ASSEMBLY TO THE PARTITION AND ONE OF SAID SHEEL SIDE MEMBERS, REVERSING FLOW MEANS IN COMMUNICATION WITH SAID TUBULAR MEMBERS SECURED TO ONE OF SAID TUBE SHEETS, SAID TUBE ASSEMBLY BEING CONSTRUCTED SO THAT THE END SUPPORTING SAID REVERSING FLOW MEANS MAY BE INSERTED INTO THE ENCLOSURE AND THE TUBE ASSEMBLY SUPPORTED THEREIN. 